Recently, a powdery mildew on the leaves of Capsium spp., Pimento and pepper, occurred greatly in the vinyl-house at Seungchon area, Chonnam province. According to the field survey, the disease is severe at high temperature and high humidity conditions in the vinyl house. Diseased loaves were severely fallen and remained only several top leaves, thus the setting and thickening of fruits were greatly depressed. The pathogenic fungus was identified as Oidiopsis taurica(Lev.) Arn., imperfect stage of Leveillula taurica (Lev.) Arn., The perfect stage of fungus was not observed. Optimum temperatures for conidial germination ranged at $25-30^{circ}C$ with high humidity.